Administering an injection is a process which presents a number of risks and challenges for users and healthcare professionals, both mental and physical.
Drug delivery devices that are capable of delivering medicaments from a medication container typically designed as manual devices or auto-injectors.
In particular, with a manual device the user must provide the mechanical energy to drive the fluid through the needle. This is typically done by an actuation head coupled to a plunger that has to be continuously pressed by the user during the injection. If the user stops pressing the actuation head then the injection will also stop. This means that the user can deliver an underdose if the device is not used properly (i.e. the plunger is not fully pressed to its end position). Some manual devices are triggered when the user pushes the actuation head complete until the end of the drug delivery process. Usually, the trigger force, which has to overcome, is increased compared to the pure injection force of the drug. This increased force is only sensible on the last one to seven millimeters of the complete device stroke. Because this is on the last millimeters of the stroke, the user gets the impression that the drug delivery process is completed, stops pushing and therefore safety mechanisms/devices for covering the needle will not be activated.